Stove warning device

ABSTRACT

Apparatus for operating a warning device such as a lamp to indicate that the burners on an electric stove are hot. A switch for the warning device is connected to a first control circuit that sets the switch in a mode completing a continuous energizing path for the device, and to a second control circuit that causes an intermittent completion of the energizing path. The control circuits operate sequentially to produce a first warning signal when one or more of the burners are on, and a different warning signal for a predetermined period of time after the burners have been turned off. Intermittent operation is achieved on a preferred embodiment by connecting various stages of a binary counter in the second control circuit.

1451 Dec. 3, 1974 STOVE WARNING DEVICE [75] Inventor: Willard A. Flagg,Jr., Topsfield,

Mass.

Ark-Les Switch Corporation, Watertown, Mass.

22 Filed: Oct. 29, 1973 21 Appl. No.: 410,809

[73] Assignee:

[52] US. Cl...' 340/227 R, 219/453, 126/39 J, 307/117, 340/228 [51] Int.Cl. H05b 3/68 [56] References Cited UNITED STATES PATENTS 2,735,9242/1956 Shaw 219/453 X 3,186,472 6/1965 Caravella..

Perl .1 126/39 J X Kircher 219/269 X Primary Examiner-John W. CaldwellAssistant Examiner-Wil1iam M. Wannisky Attorney, Agent, or Firm-MartinKirkpatrick [57] ABSTRACT Apparatus for operating a warning device suchas a lamp to indicate that the burners on an electric stove are hot. Aswitch for the warning device is connected to a first control circuitthat sets the switch in a mode completing a continuous energizing pathfor the device, and to a second control circuit that causes anintermittent completion of the energizing path. The control circuitsoperate sequentially to produce a first warning signal when one or moreof the burners are on, and a different warning signal for apredetermined period of time after the burners have been turned off.Intermittent operation is achieved on a preferred embodiment byconnecting various stages of a binary counter in the second controlcircuit.

3,529,584 9/1970 Celaya 3,612,826 10/1971 'Deaton 1. 219/506 x 14ClalmS, 8 Drawing Flgures WARN I NC orv 1C1 VOLTAGE PULSE GATE Lil-S1ABLE ALTERNAlljN SOURCE 2O l-CRMER ALTERNATlDN COUNTER 24 \22 2e 2s30 32 34 TCH BURNth CIRCUITS PATENIEL W I saw 20F FIG. 3

' e2 54 52 58\ BINARY COUNTER e4 L I A ND} I D RESET I2 BURNERS OFF A BTIME PATENIELBEB 31914 3.852.728

sum 3 or 5 64 BINARY COUNTER BURNERS OFF TIME -I FIG. 6B LAMP OFF TIME Ql STOVE WARNING DEVICE BACKGROUND OF THE INVENTION This inventionrelates to apparatus for operating a warning device to indicateoperation of an electric stove, and more particularly to apparatus foroperating a warning device in a given manner when the stove is energizedand in a different manner for a period of time after the stove has beende-energized.

The burner coils of electric stoves can become hot enough to inflictvery serious burns if they are touched. At their highest temperaturesthe coils generally glow brightly, but the glowing is not so evident atlower temperature settings and may give little or no indication that thecoils are hot. The problem is particularly acute in the case ofstovesnow becoming popular that feature a smooth glass top hiding the burners.With these stoves there is no visible sign that the glass top is hoteven for the highest settings. It is therefore desirable that some meansbe provided to indicate when the burners are in use.

- The dangerous situation continues after the electric flow through thecoils has been turned off, as the burners will remain hot for a periodof time and cool off only gradually. Some sort of warning device duringthis period is consequently also important. If, however, the samewarning mechanism is provided for both the period when the burners areenergized and the subsequent period when they are de-energized but'stillhot, a person using the stove may attempt to cook on one of the burnerswhen it is actually turned off and in the process of cooling.

SUMMARY OF THE INVENTION Apparatus is provided according to the presentinvention to operate awarning device for an electric stove in a mannerthat gives an adequate and intelligent warning in view of theabove-stated considerations.

I The invention broadly comprehends an energizing circuit for thewarning device that includes a switch means that governsthe operation ofthe warning .device. A first control signal is applied-to the switchmeans by means communicating with the burner circuits when at least oneof the burner circuits is energized, while means are provided forapplying a second control signal to the switch means followingdeenergization of all the burner circuits. Timing means terminate theapplication of the second control signal to the switchmeans apredetermined period of time after all the burner circuits arede-energized, the said predetermined time period preferably beingapproximately equal to the time required by the electric burners tocool.

In the preferred embodiment, first circuit means are adapted whenconnected to the burner circuits to continuously set the switch means ina .mode completing a path for energizing the warning device. Secondcircuit means include means alternatable between states respectivelysetting and not setting the switch means in a mode completing a warningdevice energizing path. The embodiment includes means for applying acontrol signal from one of the circuit means to the switch means when atleast one of the burner circuits is energized, and for applying acontrol signal from the other circuit means to the switch meansfollowing deenergization of all the burner circuits. Application of acontrol signal from the last circuit means to operate is terminated apredetermined period of time after all the burner circuits arede-energized. With this embodiment the hazardous condition existing whenthe burners are operated is distinguished from the condition when theburners are still hot but in the process of cooling off, by a continuousoperation of the warning device during one period and an intermittentoperation thereof during the other period. In a more particularembodiment of this feature the apparatus includes a binary counter, thealternatable means comprising one stage of the counter, and the controlsignal is terminated by means that includes an actuator comprising ahigher order stage of the binary counter.

In one particular embodiment of the invention, the warning device iscontinuously operated when the burner circuits are energized, andperiodically energized and de-energized for a predetermined period oftime following de-energization of all the burner circuits by bi-stablemeans in controlling communication with the switch means. Means areincluded for alternating the bi-stable means, an actuator being providedto initiate operation of the alternating means in response tode-energization of the burner circuits. According to one feature of thisembodiment, the alternating means comprises a binary counter incombination with and controlled by a substantially constant frequencypulse source, the frequency of the pulse source being a whole numberpower of two multiple of the alternation rate,

andthe bi-stable means comprises a stage of the binary counter.

In another aspect of the invention employing a binary counter with aplurality of stages and circuit means connectable to the burner circuitsand in controlling communication with the switch means, the circuitmeans are adapted continuously to set the switch means in a modecompleting an energizing path for the warning device when at least oneof the burner circuits is energized. The circuit means is connected toreset the binary counter to an initial count when at least one of theburner circuits is energized. The switch means is also controlled bylogic circuitry that has an input from a first stage of the binarycounter, the logic circuitry being adapted to set the switch means in amode com-- pleting the warning device energizing path when the saidfirst counter stage is in a non-reset state. A second, higher orderstage of the counter is connected to terminate counter operation whenthe second stage is in a non-reset state. The circuit means is connectedto inhibit counting by the binary counter when at least one of theburner circuits is energized. The binary counter and logic circuitry maybe provided in the form of an integrated circuit, and the inventionpreferably includes means for converting normal house voltage to aseries of pulses suitable for application to the counter.

invention;

FIG. 3 is a circuit diagram of an embodiment incorporating the featuresof FIG. 2;

the operation of a warning device controlled by the circuit of FIG. 5.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS The present invention issuitable for operating a warning device used with an electric stove 2such as the one shown in FIG. 1, which has a smooth glass top 3overlying and hiding from view a plurality of burner coils 4, 6, 8, and(shown by dashed lines), and a set of controls 12 for. operatingindividual electrical circuits associated with each of the coils. Awarning device'such as a neon lamp I4 is provided to warn that the areaof at least one of the burners is too hot to touch. As the burnersremain hot for a period of time after their controls 12 have been turnedoff, the apparatus described herein gives a warning that spans the fulldangerous period by energizing the warning lamp 14 both when one or moreof the burners are on, and also for a period of time after they havebeen turned off. Two different modes for operating the lamp are providedto distinguish the two conditions. Other warning devices such as buzzerscould also be used, but a visual indication is most desirable.

Referring now to FIG. 2, apparatus is shown in block diagram form foroperating a warning device 16 in response to heating of electric stoveburners 18. An energizing circuit for the warning device 16 includes aterminal 20 connectable to a suitable voltage source 22 such as thehouse electrical system, and a controlled switch 24 connected tocomplete or interrupt an energizing path for the warning device 16.While a single switch and warning device areshown, a plurality of suchelements may be provided, one for each of the warning device operatingmodes comprehended by my invention. In the preferred embodiment,however, only one of each element is used. A pulse forming circuit 26 isconnected to voltage source 22 and applies a series of pulses to a gate28. The output of gate 28 is connected to a bi-stable alternator 30, theoutput of which is in turn fed to a device 32 that counts the number ofalternations by alternator 30, and to another gate 34.

An output from alternation counter 32 is applied back to each of gates28 and 34. The output of gate 34 is connected over lead 36 to thecontrol for switch means 24. A signal indicating operation of burners 18is also applied to the control for switch means 24 via lead 36, and inaddition is applied to a reset input for bi-stable alternator 30.

When one or more of the burners 18 are operated, a reset signal iscontinually applied to the bi-stable alternator 30, inhibiting it fromproducing an output. The burner signal is also applied directly overlead 36 to switch means 24, causing it to complete a continuousenergizing path for the warning device 16 between the voltage source andground. The warning device 16 remains energized for as long as one ofthe burners 18 is on. When all of the burners l8 are turned off, thesaid signal to switch means 24 disappears. At the same time,

the reset signal is removed from bi-stable alternator 30, which beginsto alternate between the production of an active output and no outputeach time a pulse is applied from pulse former 26 via gate 28. Activealternator outputs are passed through gate 34, over lead 36, to setswitch means 24 in a mode completing the energizing path for warningdevice 16. When there is no output from bi-stable alternator 30 theswitch means 24 is set in a mode preventing completion of the energizingpath. The warning device 16 is thus alternately turned on and off afterthe burners 18 have been de-encrgized. After a predetermined number ofalternations, as determined by alternation counter 32, blocking signalsare applied to gates 28 and 34 to prevent the passage of any futurepulses to bi-stable alternator 30 and to prevent any output from thealternator 30 from reaching switch means 24. The warning device 16remains inactive until one of the burners 18 is again turned on, settingswitch means 24 in a mode again completing the energizing path andresetting bi-stable alternator 30.

A circuit is shown in FIG. 3 that embodies the features illustrated inFIG. 2. House voltage is applied between a terminal 38 and the groundedemitter of a switching transistor 40. A diode 42 rectifies the signal atterminal 38. A neon lamp 44 serving as the warning device is connectedto terminals 46 and 48 in an energizing path that extends from terminal38, through diode 42 and transistor 40, to ground, the energizing pathalso including a current limiting resistor 50.

Lead 52 is connected between a pair of voltage dividing resistors 54 and56 as an input to AND gate 58, the output of which is connected to thefirst stage 60 of a binary counter 62. An output from the last counterstage 64 is connected through an inverter 66 as a second input to ANDgate 58 and to an input of an AND gate 68. The output from anintermediate counter stage 70 is connected to another input of AND gate68, the output of which is applied to the base of transistor 40 throughdiode 72 and lead 74. Each of the burner circuits 76, 78, 80,.and 82 isconnected through diode 84 directly to a reset control 86 for the binarycounter 62, and to the base of transistor 40 through diode 84, diode 86,and lead 74.

When one or more of the burner circuits 76, 78, 80, and 82 areenergized, binary counter 62 is continuously reset and inhibited fromcounting. At the same time, a signal is applied from the burner circuitsto the base of transistor 40 over the circuit described above, elevatingthe voltage at the transistor base to drive the collectoremitter circuitof the transistor 40 into a conducting mode to complete the energizingpath for lamp 44, which stays on for as long as at least one of theburner circuits remains energized.

The condition existing at the moment all the burner circuits becomede-energized is as follows: binary counter 62 is reset to a count ofzero, there is no output from counter stage 64, and inverter 66 isproducing a positive output to AND gates 58 and 68. Shortly thereafter,binary counter 62 begins to count under the influence of pulses arrivingat stage 60 from AND gate 58. In this embodiment the initial stages ofthe binary counter through stage 70 function as the bi-stable alternator30 of FIG. 2, while the remaining stages provide the alternation counter32. Counter stage 70 alternates between producing a positive input andno input to AND gate 68 at a rate determined by the frequency of thepulses applied to the counter 62 and by the order of stage 70 within thecounter. The voltage level at the base of transistor 40 is respectivelyraised and lowered each time counter stage 70 produces a positive outputor a zero output, flashing lamp 44 on and off. When stage 70 hasoperated a sufficient number of times to cause a change of state ofstage 64, that stage produces a positive output and the output ofinverter 66 goes to zero, preventing the passage of any further signalsthrough AND gates 58 and 68. The binary counter 62 is thus preventedfrom operating until the end of another reset cycle, followingre-energization of the burner circuits.

When normal 60 hz. house voltage is used, 60 pulses per second areapplied to the first binary counter stage 60, causing it to turn on 30times per second and to turn off 30 times per second. The lamp 44 can bemade to go through an on-off flash cycle approximately once each secondby selecting the sixth stage of the binary counter 62 for intermediatestage 70. Flashing of the lamp 44 will terminate in approximately 35minutes, by which time the burner coils are generally cool enough totouch, by selecting stage 64 to be the last stage of an lS-stagecounter.

FlGS. 4A and 4B illustrate the operation ofthe warning device when oneor more of the burners are turned on at a time A and turned off at atime B. Referring to FIG. 4B, the lamp 44 is continuously energizedduring the time A-B under the influence-of a signal applied to the baseof transistor 40 from the burner circuits. After time B, the binarycounter 62 begins to operate and the lamp goes off until stage 70 makesan initial change of state at time C and delivers a signal through ANDgate 68, diode 72, and lead 74 to the base of transistor 40. Thereafterthe lamp 44 flashes on and off until time D, when stage 64 changes stateand discontinues operation of the counter 62.

Another embodiment of the invention that operates a warning device in amanner opposite to that described above, i.e., intermittently when thestove burners are energized and continuously'for a predetermined periodof time'after the burners are de-energized, is shown in FIG. 5. Severalof the circuit components are the same as in H6. 3, and the numeralsemployed in that figure are retained for the common elements.

in the embodiment of FIG. 5 the burner circuits 78-82 and theintermediate binary counter stage 70 control an AND gate 88, the outputof which provides a first switching signal for transistor 40. A secondswitching signal is derived from a circuit comprising an AND gate 90, aninverter 92 connected between the burner circuits 76-82 and an input toAND gate 96, and the inverter 66 connected between the output terminalof binary counter stage 64 and a second input to AND gate 90. Binarycounter stage 64 is also connected through a series circuit includingAND gate 94,

' inverter 96, and AND gate 98 to the first binary counter stage 60. Theoutput of inverter 92 provides a second input to AND gate 94, while thepulse forming circuit is connected by lead 52 as a second input to ANDgate 98. A resetting circuit for binary counter 62 comprises AND gate100 controlling the binary counter reset 86, and having a first inputfrom burner circuits 76-82 and a second input from the binary counterstage 102 that is one order higher than stage 70.

initially, the binary counter 62 is left at the count of stage 64 fromthe previous operation, thereby providing a gating signal to AND gate 94and a blocking signal to AND gate 90 from stage 64. The other input toAND gate 94 is also positive, producing a positive output signal that isprocessed by inverter 96 to block AND gate 98 from passing pulses to thebinary counter 62.

When one or more of the burner circuits 76-82 is energized, the blockingsignal is removed from AND gate 98 and the binary counter 62 begins tooperate. A gating signal is provided for transistor 40 when counterstage turns on, thereby completing the energizing circuit to switch lamp44 on. The lamp is subsequently switched off when counter stage 102turns on and stage 70 turns off. At the same time the reset circuit iscompleted to reset the binary counter 62 to zero and repeat the abovecycle. The lamp 44 continues to flash on and off for as long as at leastone of the burner circuits 76-82 is energized. It will be noted that thebinary counter 62 is reset each time the count reaches the level ofstage 102, thereby precluding an operation of the last stage 64.

When all the burner circuits 76-82 are turned off, their input to ANDgate 100 is also terminated, locking out the reset circuit. An enablingsignal appears at AND gate 94 from inverter 92, but operating pulses arestill transmitted to the binary counter 62- from lead 52 because theother input to AND gate 94 remains off. AND gate commences to produce apositive output, gating transistor 40 to continuously energize lamp 44.The reset circuit being locked out, no restraint is imposed on binarycounter 62 and it continues to count for the desired period of timeuntil stage 64 turns on. That occurrence removes the output from ANDgate 90, turning lamp 44 off, and further completes a positive set ofinputs for AND gate 94 to disable AND gate 98 and prevent any furtherpulses from reaching binary counter 62. The circuit remains in thisstate until a burner circuit is again energized, thereby removing therestraint imposed by AND gate 94 and permitting renewed operation ofbinary counter 62.

While particular embodiments of the invention have been shown anddescribed, modifications thereof will be apparent to those skilled inthe art. For example, other sequences for operating the warning devicein a first mode when one of the burner circuits is active and in asecond mode for a predetermined period of time after the burner circuitshave been turned off may be invisioned. Therefore, it is not intendedthat the invention be limited to the disclosed embodiments or to thedetails thereof, and departures may be made therefrom within the spiritand scope of the invention as defined in the claims.

What is claimed is: i 1. Apparatus for operating a warning device foruse with a stove having one or more electric burner circuits,comprising:

an energizing circuit for said warning device, including a switch meansgoverning the operation of said warning device, I a first controlcircuit for said switch means, said control circuit having means toreceive a signal indicating operation of at least one of the burnercircuits, and means to set said switch means in a mode completing anenergizing path for the warning device during receipt of said burneroperation signal, and

a second control circuit for said switch means, in-

cluding bi-stable means alternatable in response to discontinuedoperation of said burner circuits between first and second statesrespectively setting and not setting 'the switch'means in a modecompleting an energizing path for the warning device, means to alternatesaid bi-stable means, and means to terminate operation of said bi-stablemeans after a predetermined number of alternations.

2. Apparatus as claimed in claim 1, wherein said bistable meanscomprises a stage of a binary counter.

3. Apparatus for operating an electrical warning device for use with astove having one or more burner circuits, comprising:

an energizing circuit for said warning device, including a switch meansgoverning the operation of said warning device,

circuit means connectable to said burner circuits and in controllingcommunication with said switch means, said circuit means adapted when soconnected to continuously set said switch means in a mode completing anenergizing path for said warning device when at least one of the burnercircuits ,is energized,

bi-stable means in controlling communication with said switch means,alternatable between first and second states respectively setting andnot setting said switch means in a mode completing an energizing pathfor said warning device,

means for alternating said bi-stable means between said first and secondstates at a predetermined rate of alternation,

an actuator adapted to initiate operation of said alternating means inresponse to de-energization of all the burner circuits, and

means to terminate alternating operation of said bistable means apredetermined period of time after such operation is initiated.

4. Apparatus as claimed in claim 3 wherein said alternating meanscomprises a binary counter in combination with and controlled by asubstantially constant frequency pulse source, the frequency of saidpulse source being a whole number power of two multiple of saidpredetermined alternation rate, and said bi-stable means comprises astage of said binary counter.

5. Apparatus for operating an electrical warning device for use with astove having one or more electric burner circuits, comprising:

an energizing circuit for said warning device, said circuit including aswitch means governing the operation of said warning device,

circuit means connectable to said burner circuits and in controllingcommunication with said switch means, said circuit means adapted when soconnected to continuously set said switch means in a mode completing anenergizing path for said warning device when at least one of the burnercircuits is energized,

a binary counter having a plurality of stages, said circuit means beingconnected to reset said counter to an initial count when at least one ofthe burner circuits is energized,

logic circuitry in controlling communication with said switch means andhaving an input from a first stage of said counter, said logic circuitryadapted to set said switch means in a mode completing an energizing pathfor said warning device when said first counter stage is in a non-resetstate, and

a second, higher order stage of said counter connected to terminatecounter operation when said second stage is in a non-reset state.

6. Apparatus according to claim 5, wherein said binary counter and logiccircuitry are in the form of an integrated circuit.

7. Apparatus according to claim 5, wherein said circuit means isconnected to inhibit counting by said binary counter when at least oneof the burner circuits is energized.

8. Apparatus according to claim 5, useful for operating an electricalwarning light by continuously energizing the light when one of theburner circuits is encrgized, and for flashing the light for apredetermined period of time following de-energization of all the burnercircuits.

9. Apparatus according to claim 5, and further including means connectedas an input to the counter for converting normal house voltage to aseries of pulses suitable for application to said counter.

10. Apparatus for operating a warning device for use with a stove havingone or more electric burner circuits, comprising:

an energizing circuit for said warning device, said circuit including aswitch means governing the operation of said warning device,

first circuit means connectable to said burner circuits and incontrolling communication with said switch means, adapted when soconnected to continuously set said switch means in a mode completing anenergizing path for said warning device,

second circuit means in controlling communication with said switchmeans, including means alternatable between states respectively settingand not setting said switch means in a mode completing an energizingpath for said warning device,

means for applying a control signal from one of said circuit means tosaid switch means when at least one of said burner circuits isenergized, and for applying a control signal from the other of saidcircuit means to said switch means following deenergization of all ofsaid burner circuits, and

means for terminating the application of a control signal from the lastmentioned circuit means to said switch means a predetermined period oftime after all of said burner circuits are de-energized.

11. Apparatus as claimed in claim 10, wherein said alternatable meanscomprises a stage of a binary counter.

12. Apparatus as claimed in claim 11, wherein said means for terminatingthe application of a control signal includes an actuating meanscomprising a stage of said binary counter of higher order than saidalternatable means stage.

13. Apparatus for operating a warning device for use with a stove havingone or more electric burner circuits, comprising:

an energizing circuit for said warning device, said circuit including aswitch means governing the operation of said warning device,

means communicating with said burner circuits for applying a firstcontrol signal to said switch means when at least one of said burnercircuits is energized,

means for applying a second control signal to said switch meansfollowing de-energization of all of said burner circuits,

predetermined period of time after which application of the secondcontrol signal to the switch means is terminated is approximately equalto the time required by the electric burners to cool.

1. Apparatus for operating a warning device for use with a stove havingone or more electric burner circuits, comprising: an energizing circuitfor said warning device, including a switch means governing theoperation of said warning device, a first control circuit for saidswitch means, said control circuit having means to receive a signalindicating operation of at least one of the burner circuits, and meansto set said switch means in a mode completing an energizing path for thewarning device during receipt of said burner operation signal, and asecond control circuit for said switch means, including bistable meansalternatable in response to discontinued operation of said burnercircuits between first and second states respectively setting and notsetting the switch means in a mode completing an energizing path for thewarning device, means to alternate said bi-stable means, and means toterminate operation of said bi-stable means after a predetermined numberof alternations.
 2. Apparatus as claimed in claim 1, wherein saidbi-stable means comprises a stage of a binary counter.
 3. Apparatus foroperating an electrical warning device for use with a stove having oneor more burner circuits, comprising: an energizing circuit for saidwarning device, including a switch means governing the operation of saidwarning device, circuit means connectable to said burner circuits and incontrolling communication with said switch means, said circuit meansadapted when so connected to continuously set said switch means in amode completing an energizing path for said warning device when at leastone of the burner circuits is energized, bi-stable means in controllingcommunication with said switch means, alternatable between first andsecond states respectively setting and not setting said switch means ina mode completing an energizing path for said warning device, means foralternating said bi-stable means between said first and second states ata predetermined rate of alternation, an actuator adapted to initiateoperation of said alternating means in response to de-energization ofall the burner circuits, and means to terminate alternating operation ofsaid bi-stable means a predetermined period of time after such operationis initiated.
 4. Apparatus as claimed in claim 3 wherein saidalternating means comprises a binary counter in combination with andcontrolled by a substantially constant frequency pulse source, thefrequency of said pulse source being a whole number power of twomultiple of said predetermined alternation rate, and said bi-stablemeans comprises a stage of said binary counter.
 5. Apparatus foroperatinG an electrical warning device for use with a stove having oneor more electric burner circuits, comprising: an energizing circuit forsaid warning device, said circuit including a switch means governing theoperation of said warning device, circuit means connectable to saidburner circuits and in controlling communication with said switch means,said circuit means adapted when so connected to continuously set saidswitch means in a mode completing an energizing path for said warningdevice when at least one of the burner circuits is energized, a binarycounter having a plurality of stages, said circuit means being connectedto reset said counter to an initial count when at least one of theburner circuits is energized, logic circuitry in controllingcommunication with said switch means and having an input from a firststage of said counter, said logic circuitry adapted to set said switchmeans in a mode completing an energizing path for said warning devicewhen said first counter stage is in a non-reset state, and a second,higher order stage of said counter connected to terminate counteroperation when said second stage is in a non-reset state.
 6. Apparatusaccording to claim 5, wherein said binary counter and logic circuitryare in the form of an integrated circuit.
 7. Apparatus according toclaim 5, wherein said circuit means is connected to inhibit counting bysaid binary counter when at least one of the burner circuits isenergized.
 8. Apparatus according to claim 5, useful for operating anelectrical warning light by continuously energizing the light when oneof the burner circuits is energized, and for flashing the light for apredetermined period of time following de-energization of all the burnercircuits.
 9. Apparatus according to claim 5, and further including meansconnected as an input to the counter for converting normal house voltageto a series of pulses suitable for application to said counter. 10.Apparatus for operating a warning device for use with a stove having oneor more electric burner circuits, comprising: an energizing circuit forsaid warning device, said circuit including a switch means governing theoperation of said warning device, first circuit means connectable tosaid burner circuits and in controlling communication with said switchmeans, adapted when so connected to continuously set said switch meansin a mode completing an energizing path for said warning device, secondcircuit means in controlling communication with said switch means,including means alternatable between states respectively setting and notsetting said switch means in a mode completing an energizing path forsaid warning device, means for applying a control signal from one ofsaid circuit means to said switch means when at least one of said burnercircuits is energized, and for applying a control signal from the otherof said circuit means to said switch means following de-energization ofall of said burner circuits, and means for terminating the applicationof a control signal from the last mentioned circuit means to said switchmeans a predetermined period of time after all of said burner circuitsare de-energized.
 11. Apparatus as claimed in claim 10, wherein saidalternatable means comprises a stage of a binary counter.
 12. Apparatusas claimed in claim 11, wherein said means for terminating theapplication of a control signal includes an actuating means comprising astage of said binary counter of higher order than said alternatablemeans stage.
 13. Apparatus for operating a warning device for use with astove having one or more electric burner circuits, comprising: anenergizing circuit for said warning device, said circuit including aswitch means governing the operation of said warning device, meanscommunicating with said burner circuits for applying a first controlsignal to said switch means when at least one of said burner circuits isenergized, means for applying a secoNd control signal to said switchmeans following de-energization of all of said burner circuits, andtiming means for terminating the application of said second controlsignal to said switch means a predetermined period of time after all ofsaid burner circuits are de-energized.
 14. Apparatus as claimed in claim13, wherein said predetermined period of time after which application ofthe second control signal to the switch means is terminated isapproximately equal to the time required by the electric burners tocool.